1. Field of the Invention
The present invention relates generally to a lancet device. Particularly, the present invention relates to a single use lancet device that prevents re-use of the lancet.
2. Description of the Prior Art
Lancets are well-known devices commonly used in the medical field to make small punctures in a patient's skin in order to obtain samples of blood. They are utilized in hospitals, other medical facilities and by private individuals such as diabetics for testing droplets of blood for various analytes. Typically, lancets are used only once in order to reduce the risk of HIV, hepatitis and other bloodborne diseases. The needle of these devices is driven into the patient's skin by a small spring that is cocked by a technician or user prior to use. The needle is covered with a protective, safety cap that is removed before use. The safety cap keeps the end of the lancet sterile and is typically used as a kind of pushrod for arming the device. After arming the device, the safety cap is removed exposing the needle and the lancet is ready for use.
There are a variety of lancet devices that are available for utilization by patients and/or practitioners in a variety of different circumstances. One variety is configured for multiple and/or repeated uses. This variety typically includes a lancet injector that projects a lancet toward the skin of a patient that is pushed by the user. More commonly, the lancet device effectively encases and fires the lancet into the patient's skin in order to puncture in an accurate, standardized and consistent manner. The lancet injector may also be provided with an adaptor cap to control and adjust the depth of penetration of the needle of the lancet.
Another variety is configured for single use where the entire device is discarded after use. Typically, these devices include a housing that contains and directs or drives a piercing tip into the patient's skin and then is discarded along with the used lancet. Such devices are effective for achieving the piercing of the skin required for effective operation. These single-use, disposable devices, however, typically do not incorporate a large number of safety features to ensure safe use and disposal of the device. A major disadvantage of such devices is that they can be inadvertently re-used. The configuration of these devices is such that a user can re-cock the device and allow for subsequent and inappropriate use of a contaminated lancet.
There have been some devices developed that affirmatively prevent re-use of a single use lancet. U.S. Pat. No. 5,423,847 (1995, Strong et al.) discloses a safe lancet injector. The safe lancet injector for use with a lancet and an isolating platform to obtain blood samples for diagnostic purposes. The lancet injector uses two elastomeric bands to push the lancet forward and to rapidly withdraw the needle from the skin. It further includes an interlocking mechanism that completely precludes a lancet from being used more than once, which causes the used lancet to be ejected before cocking/arming the lancet injector can be performed.
U.S. Pat. No. 6,168,606 (2001, Levin et al.) discloses a single-use, spring-driven lancet device. The device is precocked during assembly so that the user needs only to remove the safety cap prior to use. A thin plastic fiber connection between the pull-tab and the needle safety cap prevents any compressive force from being applied to the drive spring, which prevents recocking/re-arming of the device.
U.S. Pat. No. 6,514,270 (2003, Schraga) discloses a single use lancet device having a housing, a lancet with a piercing tip movably disposed in the housing and structured to move between a cocked orientation and a piercing orientation, and a driving assembly structured to move the lancet into the piercing orientation. A retention member and an engagement hub are provided and structured to cooperatively engage with one another when the lancet is disposed into the cocked orientation until released by an actuation assembly. The actuation assembly is structured to move between an actuated and an un-actuated orientation. Movement of the actuation member into the actuated orientation releases the retention member and the engagement hub from their cooperative engagement with one another resulting in the movement of the lancet into the piercing orientation. A restrictor assembly prevents the actuation assembly from moving out of the actuated orientation and prevents re-firing of the lancet using the actuation assembly.
These devices, however, are only lancet devices and must be used with separate test strips for making an analyte determination on the sample of blood produced by the lancet device.
There has also been developed integrated lancet and sensor devices that combine the lancet and test strip into a single package. These integrated devices are typically used with a lancet injector where the integrated lancet and test strip is removed from the lancet injector and connected to a meter after acquisition by the test strip of the blood sample produced by the lancet, or used with a meter with built-in lancet injector.
One such integrated device is disclosed in U.S. Patent Application Publication 2007/0149897 by Ghesquiere et al. The device is an integrated lancet and testing striplet for measuring a body analyte level in a health care regimen that includes a lancet needle and an analyte sensor coupled together. A lancet body includes a sensor receiving end and a lancet end. The lancet needle is coupled with and protruding from the lancet end. The sensor is coupled to the sensor receiving end of the lancet body. The integrated device is positioned within a rotating cradle and, during the assay or after completion of the assay, the cradle is rotated by mechanical transmission to position the lancet for re-attaching the protective cover to the used lancet of the lancet-test strip combination.
U.S. Patent Application Publication 2006/0020228 (2006, Fowler et al.) discloses an integrated lancet and test strip. The assembly includes a lancet disposed within a lancet enclosure where the lancet moves between a retracted position and an extended position out of a needle end of the lancet enclosure, and an elongated test strip having a sample receiving end disposed at the needle end of the lancet enclosure. After piercing the skin, the lancet is retracted into the lancet enclosure so that it is not exposed to prevent accidental piercing.
A major disadvantage of these integrated lancet and test strip devices is the lack of a safety mechanism to prevent re-firing/re-use of a used integrated device. Prior art devices can be inadvertently re-fired by simply re-cocking the firing mechanism, which can lead to inadvertent and accidental skin punctures with a used lancet.
Therefore, what is needed is lancet device that is a single use lancet with a safety mechanism to prevent re-use. What is also needed is an integrated lancet and test strip device where the lancet portion cannot be re-fired/re-used.